1. Field of the Invention
This invention relates a magnetic tape cassette for recording and reproducing a digital signal, and more particularly to a tape cassette such as a video tape cassette, an 8 mm tape cassette or the like which has a tape wound on reels.
2. Description of the Related Art
There has been widely used a magnetic tape cassette for a PCM recording and reproducing apparatus which is adapted to convert an analog signal such as an acoustic signal or the like to a digital signal such as a PCM signal to record it on a magnetic tape or reproduce the recorded signal from the tape. The magnetic tape cassette used for such a purpose is provided with a brake mechanism including brake members or reel brakes. The brake members function to regulate revolution of a pair of reels which have a magnetic tape wound thereon, to thereby prevent looseness of the magnetic tape in non-use of the tape cassette. In use of the tape cassette, the reel brakes are kept released from engagement with the reels by means of a release means arranged on the side of a tape deck for driving or operating the tape cassette, so that the reels may be rotated.
Also, in the brake mechanism of the conventional tape cassette, the brake members each are supported on a shaft provided in a cassette casing or the like and a release lever arranged in a cassette casing is actuated through the release means of the deck while being forced by means of a spring, so that the release lever functions to selectively carry out engagement of the brake members with the reels and release of the brake members from engagement with the reels.
Unfortunately, the conventional tape cassette causes an area for setting the brake mechanism to be substantially reduced because it is arranged between both reels so as to be positioned opposite to the center of a front lid of the cassette casing, resulting in failing to permit the rotational displacement of the reel brakes or brake members due to movement of the release lever in the setting area to be carried out. This causes a reduction of rotational movement of the brake members, resulting in the braking action being rendered unstable, so that the brake mechanism fails to exhibit a satisfactory braking function.
Also, in the prior art, the reel brakes are caused to continue rotation or pivotal movement while the release lever is moving while contacting with the reel brakes, so that an area necessary for the brake release operation larger than that necessary for movement of the reel brakes is required in addition to the latter area.